The effect of cesarean delivery on the neonatal gut microbiome in an under-resourced population in the Bronx, NY, USA

Abstract

Background: Neonatal and early-life gut microbiome changes are associated with altered cardiometabolic and immune development. In this study, we explored Cesarean delivery effects on the gut microbiome in our high-risk, under-resourced Bronx, NY population.

Results: Fecal samples from the Bronx MomBa Health Study (Bronx MomBa Health Study) were categorized by delivery mode (vaginal/Cesarean) and analyzed via 16 S rRNA gene sequencing at four timepoints over the first two years of life. Bacteroidota organisms, which have been linked to decreased risk for obesity and type 2 diabetes, were relatively reduced by Cesarean delivery, while Firmicutes organisms were increased. Organisms belonging to the Enterococcus genus, which have been tied to aberrant immune cell development, were relatively increased in the Cesarean delivery microbiomes.

Conclusion: Due to their far-reaching impact on cardiometabolic and immune functions, Cesarean deliveries in high-risk patient populations should be carefully considered.

Keywords: Cesarean delivery; Gut Microbiome; Neonatal outcomes; Pregnancy; Under-resourced Population.

Fig. 1

Gut microbiome diversity increases from birth to 2 years of age. 16 S ribosomal RNA sequencing and analysis were performed as described in the Methods. Chao1 (P = 2.85E-06, birth vs. 6 months; P = 0.032, 6 vs. 12 months; P = 0.029, 12 vs. 24 months, Panel A) and Shannon (P = 2.60E-07, birth vs. 6 months; P = 0.15, 6 vs. 12 months; P = 0.07, 12 vs. 24 months, Panel B) plots of alpha diversity of gut microbiome from birth to age 2. Statistical significance was determined by Kruskall Wallis testing

Fig. 2

Gut microbial communities shift dramatically from birth to 2 years of age. Abundance histograms showing beta diversity between different timepoints from birth to age 2. Each bar represents the total sum of the microorganisms in all the fecal samples collected at one timepoint (birth, 6 months, 1 year or 2 years, as indicated). Each color represents a taxonomy, and the length of each color block represents the proportion of the relative abundance of the taxonomy. Four different taxonomic classification levels are shown: phylum (A), class (B), order (C) and family (D). Statistically significant differences in the abundance of specific organisms at different timepoints were found by ANCOM, as described in Results section

Fig. 3

Mode of delivery affects the composition of gut microbial communities at birth. Abundance histograms showing beta diversity between samples collected from neonates born by vaginal vs. Cesarean delivery. Each bar represents the total sum of the microorganisms in all the fecal samples collected from neonates who were born by either mode of delivery at one timepoint as shown: birth (A), 6 months (B), 1 year (C) or 2 years (D). Three different taxonomic classification levels (phylum, order, family) are shown for birth and 6 months; one taxonomic level (family) is shown for 1 year and 2 years. Increases in organisms in the Burkholderiales order and in the Neisseriacea family in Cesarean deliveries were statistically significant (W = 14 and 86, respectively, by ANCOM, Panel A.) No significant differences were found at 6, 12, or 24 months (Panels B-D)

Fig. 4

PCoA shows partial separation of the gut microbial communities based on mode of delivery. Unweighted (A) and weighted (B) PCoA of gut microbiome based on vaginal vs. Cesarean delivery

Fig. 5

Significantly increased gut micro-organisms associated with Cesarean delivery. Relative abundance of organisms belonging to the Enterococcus (A), Sphingomonas (B), Neisseria (C) and Haemophilus genuses. Neisseria and Haemophilus organisms were only detected in fecal samples from Cesarean deliveries. *P < 0.05

Fig. 6

KEGG analysis of Cesarean vs. vaginally delivered microbiomes. Significantly differentially expressed pathways are shown at birth (A), 6 months (B), 1 year (C) and 2 years (D)